[JURIST] The Nevada Supreme Court [official website] on Thursday ruled [opinion, PDF] that Nevada’s implied consent law [text], which allows police officers to take blood samples of motorists to determine impairment, is unconstitutional. The case involved a man named Michael Byars who was stopped by state troopers for driving under the influence of a controlled substance. Upon questioning the suspect the officers detected the smell of marijuana and arrested Byars, who was later subject to blood testing allowed by Nevada’s implied consent law. The Nevada Supreme court ruled that the implied consent rule as used within the case was unconstitutional because the warrantless search violated the Fourth Amendment [text]. However, the evidence found through the blood testing was not suppressed by use of the exclusionary rule because the court found the officers acted in good faith.

The Nevada Supreme Court relied on the US Supreme Court [official website] decision Missouri v. McNeely [SCOTUSblog backgrounder] which held that the fourth amendment may require a warrant [JURIST report] for a blood test in a drunk-driving investigation.The divided court ultimately held that “in drunk-driving investigations, the natural dissipation of alcohol in the bloodstream does not constitute an exigency in every case sufficient to justify a blood test without a warrant.” Last year the Minnesota Supreme Court upheld [JURIST report] the state’s driving while intoxicated implied consent law, ruling it is constitutional under the fourth amendment. In light of recent fourth amendment cases, some legal commentators have argued [JURIST op-ed] that investigative techniques have eroded the rights encompassed in the fourth amendment.